1. Field of the Invention
The present invention relates to a base station, a user apparatus and a method for use in a mobile communications system.
2. Description of the Related Art
In a mobile communications system, a reference signal is used for various purposes such as channel estimation, synchronous capturing, cell search, and receive-quality measurement, etc. The reference signal, which is a signal such that a bit value is known at the transmitter and at the receiver before communicating, may be called a known signal, pilot signal, training signal, etc. Preferably, the reference signal corresponds on a one-on-one basis to a cell ID which identifies a cell, so that it needs to be provided in multiple numbers. In an existing wideband code division multiple access (W-CDMA) system, 512 kinds of reference signals (code sequences) are provided for downlink. (See Non-patent document 1, for example.)
Non-Patent Document 1
3GPP, TS25.211 “Physical Channels and mapping of transport channels onto physical channels (FDD)”